DE10235240B4 - Solenoid valve-controlled injection nozzle - Google Patents

Abstract

Solenoid-controlled Injector with a nozzle needle, their opening and closing is controlled by a solenoid valve, wherein the solenoid valve a in a magnet pot (20) contained electromagnet (18), a An armature (16) and a valve member cooperating with a valve seat (14) (15), wherein the armature (16) is connected to an anchor bolt (28) passing through a guide sleeve (40) guided with the magnetic pot (20) at least partially surrounding the guide sleeve (40), characterized in that the Magnet pot (20) consists of a solid material and a radial slot (22) and the guide sleeve (40) and the magnet pot (20) at least partially by an exemption gap (43) are separated.

Description

Technical area

to Control of fuel injectors are often solenoid valves used. In idle state, the solenoid valve is not controlled and therefore closed. The opening time of the solenoid valve determines the start of injection of the fuel into the combustion chamber through the injector, with the closing is set the injection end.

State of the art

From the DE 695 20 464 T2 or the EP 0 318 743 A1 Such solenoid-controlled injection nozzles are known. The principle of operation of such injectors based on the fact that the nozzle needle is loaded in the closed state of the injector of ruling in a control chamber pressure in the closing direction. To initiate the injection causes the solenoid valve through its opening due to the excitation of its electromagnet, a discharge of the control chamber. As a result, the nozzle needle of the injection nozzle is lifted from its seat under the action of the other side acting on her high pressure, so that the fuel injection begins.

Such a solenoid valve is also the subject of DE 197 08 104 A1 , In this case, a solenoid valve is proposed, the magnet armature is designed in several parts and has an armature disc and an anchor bolt, which is guided in a slider. In order to avoid ringing of the armature disk after closing the solenoid valve, a damping device is provided on the armature. The solenoid valve is intended for use with common rail injection systems.

DE 100 51 549 A1 refers to a solenoid valve for controlling an injection valve of an internal combustion engine. The solenoid valve includes a magnetic armature which has a sliding on the anchor bolt part which is movable between two stops of the anchor bolt against the clamping force of a return spring. With the help of the sliding part, a momentum transfer is generated on the anchor bolt, which reduces bouncing of the armature on the valve seat.

DE 100 04 961 A1 The object of a fuel injection valve for fuel injection systems of internal combustion engines is to include a first magnetic coil interacting with an armature, a second magnetic coil interacting with the armature and a valve needle connected in a force-locking manner with the armature for actuating a valve closing body. With the first solenoid, a force in the closing direction with the second solenoid coil a force in the opening direction is exerted on the armature.

Out Bosch: Automotive Handbook [Editor-in-Chief: Horst Bauer], 23rd, updated and expanded edition, Braunschweig / Wiesbaden: Vieweg 1999, ISBN 3-528-03876.4, Page 207 is a table with sintered metals for soft magnetic components specified. these can find use in solenoid valves.

Heart of a Solenoid valve is a magnetic pot in which the coil of the electromagnet is wound up. To disturbing eddy currents In the material of the magnet pot to verhin countries, this is in the state the technology made of a composite material. It acts For example, it is a metal-polymer composite material the fine metal particles are coated with plastic. The production takes place by pressing plastic coated Metal powder and subsequent Crosslinking of the polymers. As a result of this combination of materials the metal particles are isolated from each other by the plastic matrix and thereby eddy currents prevented. The metal ensures the necessary Magnetization and power transmission on the solenoid valve member. However, the powder composite requires one reduced load capacity with respect temperature increases and mechanical loads. A magnet pot in an injector, to Example in a common rail injector, however, will be over its entire Life of high temperatures and high mechanical stress exposed. In the solenoid valve area, fuel temperatures of about 150 ° C and caused by the Absteuermenge pressure oscillations of approx. 20 bar. Another disadvantage of the powder composite material is that the plastic content the magnetization and consequently the force on the solenoid valve member reduced. Therefore, a must preferably high holding current for energizing the electromagnet and a possible size pole and therefore a big one outer diameter or one as possible small inner diameter of the magnet pot can be chosen to the required Exercise power to be able to.

Presentation of the invention

The solenoid valve-controlled injection nozzle according to the invention and the solenoid valve according to the invention avoid the disadvantages occurring in the prior art and make it possible, despite thermal and mechanical stress, to achieve a longer service life of the solenoid valve and the injection nozzle. Furthermore, the static force is exerted, which exerts the magnetic field of the electromagnet on the armature of the solenoid valve. Due to the higher static force, it is possible to lower the holding current (and thus the power loss in the Reduce control unit). In addition, the higher force potential for higher system pressures. Furthermore, the pole face can be reduced, thereby increasing the inner diameter of the magnet pot, or reducing the outer diameter, thereby providing interesting new design possibilities for the solenoid valve and injector, which in turn can reduce cost and manufacturing expense.

These Advantages are achieved according to the invention by a solenoid valve-controlled injection nozzle with a nozzle needle, their opening and closing is controlled by a solenoid valve, wherein the solenoid valve a in a magnet pot contained electromagnet, an anchor and a valve member cooperating with a valve seat.

there the magnetic pot is made of a solid material and he receives one radial slot.

By The use of the solid material is the durability of the magnet pot guaranteed even at high temperatures and strong pressure oscillations. The occurring in the solid material, compared to the metal-polymer composite higher eddy currents are suppressed by the radial slot in the magnet pot. In a preferred embodiment In accordance with the present invention, the slot interrupts at one location the annular Magnet pot completely. He will as possible narrow, a reduction of the pole area to avoid. But it is so broad that an electric Interruption is ensured so that no circular eddy currents in the Magnet pot can occur.

Of the Solid material preferably has in the present invention a high saturation induction, particularly preferably a saturation induction> 1.9 Tesla. magnetic Materials have a non-linear behavior of magnetic induction B in dependence from the magnetic field strength H of an outer field on. With increasing magnetic field strength, induction first increases, until it goes to saturation from a certain magnetic field strength. The saturation induction For example, in alloyed steels is about 1.9 Tesla, while she in cast iron at about 1.5 Tesla. The solid material used according to the invention may be due to the higher Density of the magnetic material a much higher saturation induction (for example 2 Tesla) as a composite material of the prior art (for Example 1.7 Tesla). Through the magnet pot made of solid material is therefore advantageously a significantly higher static Force to open of the solenoid valve, as in the composite magnetic pot.

Furthermore, the solid material has the smallest possible coercive field strength, preferably a coercive force <3500 A / m. If the magnetic field strength H of an external field is lowered to 0, residual magnetism remains (B> 0). The residual magnetism can be eliminated by a field in the opposite direction. The required field strength is called coercive force H _C. The smaller the coercive field strength, the lower are unwanted magnetic reversal losses. In the present invention, soft magnetic materials with H _c <3.5 × 10 ³ A / m, more preferably soft magnetic materials with H _C <1 × 10 ³ A / m are preferably used as solid materials for the magnet pot.

The Solid materials should also have good machinability and, where appropriate a good weldability exhibit. Preferred solid materials are soft magnetic FeCo alloys with a saturation induction in the range between 2.1 T and 2.3 T. The advantages of the present Invention can but also with cheaper Insert and tempered steels with sufficiently soft magnetic properties and a saturation induction> 1.9 T can be achieved.

object The present invention further includes a solenoid valve comprising an electromagnet contained in a magnet pot, an armature and a valve member cooperating with a valve seat, wherein the magnetic pot consists of a solid material and a radial Slot contains. The solenoid valve according to the invention For example, in a solenoid valve controlled according to the invention injection used.

drawing

Based the drawing, the invention is explained in more detail below.

It shows:

1 a detail of a solenoid valve-controlled injection nozzle according to the invention,

2 a section through a solenoid valve of the prior art,

3 a section through a solenoid valve according to the invention,

4 a schematic representation of the eddy currents in a magnet pot with or without slot or slot and with or without exemption gap and

5 a section through an inventive solenoid valve with shims to a make the residual air gap.

variants

1 shows a section through an injection nozzle according to the invention, which is controlled by a solenoid valve according to the invention.

In a housing 1 there is a longitudinal bore 2 in which a nozzle piston 3 is recorded. The nozzle piston 3 acts at its one end on the (not shown) nozzle needle of the injection nozzle. This nozzle needle is used to open and close injection openings of the fuel injection nozzle, through which the fuel is injected into the combustion chamber. Over the nozzle piston 3 the nozzle needle is held in the closed position, which is constantly exposed to an acting in the opening direction of high fuel pressure. The fuel under high pressure is via a pressure bore 4 running longitudinally in the housing 1 runs, fed to the injection openings. The nozzle piston 3 becomes at its one end in a guide bore 5 guided, which in a means of clamping screw 41 held in the housing nozzle piece 6 located. The face 25 of the nozzle piston 3 closes in the pilot hole 5 a control room 7 one. The control room 7 is via an inlet throttle 8th passing radially through the wall of the nozzle piece 6 runs, with a the circumference of the nozzle piece 6 surrounding annulus 9 connected. The annulus 9 stands with the pressure hole 4 in conjunction, so that the control room 7 over the annulus 9 and the inlet throttle 8th with the pressure hole 4 and the prevailing fuel high pressure is connected. From the control room 7 extends coaxially to the nozzle piston 3 a hole 10 that has an outlet throttle 11 includes. The outlet throttle 11 flows into a relief room 12 which is connected to a (not shown) fuel return of the injection nozzle. The mouth of the outlet throttle 11 in the relief room 12 is located in the region of a conically countersunk part 13 on the outside of the nozzle piece 6 in which a valve seat 14 is trained. The valve seat 14 acts with a valve member 15 a solenoid valve controlling the injector together. The valve member 15 is with an anchor 16 over a first anchor bolt 17 connected. The anchor 16 acts with an electromagnet 18 of the solenoid valve and is with the first anchor bolt 17 coupled. The anchor 16 includes an anchor plate 19 which faces the electromagnet received in a magnet pot.

According to the invention, the magnet pot is 20 , which consists of a solid material, slotted radially to eddy currents in the magnet pot 20 to avoid. This will be explained later on 4 explained in more detail. The magnet pot 20 has an axially extending, cylindrical opening 21 , The slot 22 runs radially in the opening 21 surrounding material of magnet pot 20 , The anchor 16 is on the side of the anchor plate 19 with a second anchor bolt 23 connected. The second anchor bolt 23 and with him the anchor 16 , the first anchor bolt 17 and the valve member 15 are by a fixed housing spring closing spring 24 constantly acted upon in the closing direction with a force through which the valve member 15 with non-energized electromagnet 18 on the valve seat 14 seated. The solenoid valve is therefore closed. Upon excitation of the electromagnet 18 becomes the anchor plate 19 from the electromagnet 18 tightened, so that the valve member 15 from the valve seat 14 takes off and the bore 10 with the outlet throttle 11 to the relief room 12 is opened.

The opening and closing of the injector nozzle needle (not shown) is controlled by the solenoid valve as follows:
When the solenoid valve is closed, the control room 7 through the valve seat 14 seated valve member 15 to the relief room 12 closed off. Therefore, builds in the control room 7 via the inlet throttle 8th a high pressure, which also in the (not shown) high-pressure fuel accumulator in communication pressure bore 4 prevails. Over the face 25 of the nozzle piston 3 This generates high pressure in the control room 7 a closing force on the (not shown) nozzle needle. The closing force thus generated is greater than that in the opening direction 27 forces acting on the nozzle needle by the high pressure. Through an opening of the solenoid valve is the control room 7 to the relief room 12 open, so that the high pressure in the small volume of the control room 7 fast over the drain throttle 11 degrades. The inlet throttle 8th coupled thereby the control room 7 from the high pressure side. Therefore, the force acting on the nozzle needle exceeds the force in the opening direction 27 in the closing direction 26 acting force and the nozzle needle opens the injection openings of the injection nozzle for injection by a movement in the opening direction 27 , If the solenoid valve to stop the injection, the bore 10 including outlet throttle 11 closes again, so the high pressure in the control room 7 through the over the inlet throttle 8th nachströmenden fuel rebuilt and the injector through the thereby in the closing direction 26 moved nozzle needle closed again.

2 shows a section through a solenoid valve of the prior art.

It includes one in a magnet pot 20 contained electromagnet 18 that with an anchor 16 or its anchor plate 19 interacts. The magnet pot 20 contains no slot and consists of a polymer-metal composite material. The anchor 16 is over an anchor bolt 28 with the valve member 15 of the solenoid valve connected to that in a nozzle piece 6 trained valve seat 14 interacts. A closing spring 24 causes a permanent closing force on the anchor bolt 28 , The anchor 16 includes a guide neck 29 and is against the biasing force of a return spring 30 on the anchor bolt 28 stored dynamically displaceable. This on the anchor bolt 28 displaceable arrangement of the armature 16 the purpose is to bounce the valve member 15 to avoid during operation of the solenoid valve. At rest, the anchor becomes 16 through the return spring 30 against a stop 31 at the anchor bolt 28 pressed. The return spring 30 is on the one hand at the anchor 16 on the other hand supported on a flange 33 a guide piece 32 from. This guide piece 32 serves to guide the anchor bolt 28 , It is fixed between two shims 34 . 35 sandwiched, in turn, from the solenoid valve housing 36 and a shoulder 37 of the housing 1 being held. So are the shims 34 . 35 and the leader 32 fixed together stationary. Through the thickness of the first shim 34 becomes the distance of the guide piece 32 from the valve seat 14 adjusted and thus the maximum opening stroke of the valve member 15 , The maximum opening stroke depends on the one hand on the distance of the guide piece 32 from the valve seat 14 and on the other hand, from the position of an annular shoulder attached to the anchor bolt 38 off, because this ring shoulder 38 at maximum open solenoid valve on the guide piece 32 comes to the plant. The thickness of the inner ring 47 is used to adjust the path to the slidable on the anchor bolt 28 stored anchors 16 against the force of the return spring 30 after placing the valve member 15 on the valve seat 14 can be moved during the closing of the solenoid valve. The second dial 35 (Classified adjustment ring) also influences by its thickness a residual air gap 39 between the anchor plate 19 and the magnet pot 20 which is designed so that no magnetic sticking after switching off the electromagnet 18 occurs.

3 shows a section through a solenoid valve according to the invention.

The structure of this solenoid valve according to the invention corresponds to the respect 1 described solenoid valve. The magnet pot 20 consists of a solid material and contains a (not shown) radial slot. Due to the higher saturation induction of the solid material, it was possible to increase the inner diameter of the magnet pot 20 over the prior art to increase, reduce the outer diameter and the leadership of the anchor 16 in the area of the magnet pot 20 to lay. In this preferred embodiment of the present invention, the anchor is 16 with a (second) anchor bolt 23 connected by a guide sleeve 40 is guided, with the magnet pot 20 the guide sleeve 40 at least partially surrounds. This results in an advantageous manner a more compact construction of the solenoid valve according to the invention or the injection nozzle according to the invention, since the guide piece is omitted from the prior art. The opening 42 in the clamping screw 41 does not provide guidance for the first anchor bolt 17 represents.

If the material of the guide sleeve 40 is magnetizable (and this is usually the case with curable material), so must by the geometry of the guide sleeve 40 be ensured that no excessive parasitic leakage flux over the guide sleeve ausbil det, which would lead to a large loss of power. Therefore, at the in 3 illustrated preferred embodiment of the present invention, the guide sleeve 40 and the magnet pot 20 at least partially by an exemption gap 43 separated. In a preferred embodiment of the present invention, the geometry of the guide sleeve 40 chosen so that the field lines in the area of the guide sleeve 40 be bundled, so that the field lines no longer form a disturbing leakage flux, but by bundling contribute to the force. The guide sleeve acts 40 as an additional pole surface, whereby the more compact construction of the solenoid valve according to the invention is made possible.

The exemption gap 43 is of great importance because without the exemption the slot 22 in the magnet pot 20 would be ineffective. In an inside of the magnet pot 20 adjacent guide sleeve 40 would bridge the eddy currents through the slot, so that the magnetic force build-up would be slowed down. This will be explained later on 4 explained in more detail.

For the effectiveness of the exemption is the width of the exemption gap 43 preferably a multiple, more preferably at least 8 times the width of the residual air gap 39 that is between the anchor plate 19 and the magnet pot 20 with the solenoid valve open.

Furthermore, there must also be losses over the circumference of the anchor plate 19 to the housing 1 be avoided. This is for example by a spacing of the anchor plate 19 from the case 1 reached. At the in 3 illustrated preferred embodiment has the anchor plate 19 a smaller diameter than the (to the housing 1 at a small distance) magnet pot 20 , so that between anchor plate circumference and housing 1 an exemption gap 44 located.

The exemption gap 43 and the exemption gap 44 are also in 1 displayed. Further contains 1 a detail enlargement A, which shows, as in the present invention, preferably the width of the residual air gap 39 is given. In the prior art, the residual air gap via at least one shim is set (see 2 ). This has in addition to the fact that additional parts are needed, also the disadvantage that the width of the residual air gap can not be directly measured and controlled. At the in 1 illustrated embodiment of the present invention is the width of the residual air gap 39 fixed. This is the guide sleeve 40 from the magnet pot 20 so forth that the anchor plate 19 with energized electromagnet 18 not to the magnet pot 20 but to the protruding end 45 the guide sleeve 40 abuts.

There is a fixed residual air gap 39 between the magnet pot 20 and the anchor plate 19 , which in its width is the height of the protruding end 45 the guide sleeve 40 equivalent. The width of the residual air gap may therefore be greater than the cup height relative to the length of the guide sleeve 40 to get voted.

4 shows a schematic representation of the eddy currents in a magnetic pot without ( 4a ) or with slot ( 4b ) or with slot and without ( 4c ) or with an exemption gap ( 4d ).

In the magnet pot 20 without slot according to the prior art ( 4a ) form disturbing eddy currents 46 , The eddy currents 46 slow down the magnetic force. This is prevented according to the invention by the slot 22 in the magnet pot 20 ( 4b ). The slot 22 interrupts the eddy currents.

When the guide sleeve 40 at the magnet pot 20 is present ( 4c ) can despite slot 22 disturbing eddy currents 46 flow, as the guide sleeve 40 the slot 22 bridged. This is prevented according to the invention by the clearance gap 43 ( 4d ), the magnet pot 20 from the guide sleeve 40 separates. The disturbing eddy currents are interrupted.

5 shows a section through an inventive solenoid valve with shims for adjusting the residual air gap.

At the in 5 illustrated embodiment of the present invention, the residual air gap 39 not like in 3 through the dimensions of the slotted magnet pot 20 and the guide sleeve 40 set, but by at least one adjustment ring 48 . 49 , One possibility is the insertion of a setting ring 48 in an exposed area A at the contact surface 50 of the magnet pot 20 , The adjusting ring 48 can then with the magnet pot 20 be welded. Another possibility is the insertion of a setting ring 49 in area B between the guide sleeve 40 and the anchor plate 19 , the second anchor bolt 23 surrounds.

1

casing

2

longitudinal bore

3

die rod

4

pressure bore

5

guide bore

6

nozzle piece

7

control room

8th

inlet throttle

9

annulus

10

drilling

11

outlet throttle

12

relief chamber

13

tapered countersunk Part of the nozzle piece

14

valve seat of the solenoid valve

15

valve member of the solenoid valve

16

anchor

17

first anchor bolts

18

electromagnet

19

anchor plate

20

magnet pot

21

cylindrical opening

22

slot

23

second anchor bolts

24

closing spring

25

Face of the die rod

26

closing direction

27

opening direction

28

anchor bolts

29

guide socket

30

return spring

31

attack

32

guide piece

33

flange

34

first Focusing

35

second Focusing

36

Solenoid valve housing

37

shoulder of the housing

38

annular shoulder

39

Residual air gap

40

guide sleeve

41

clamping screw

42

Opening in the clamping screw

43

Exemption gap

44

Exemption gap

45

protruding End of the guide sleeve

46

eddy currents

47

inner ring

48

first adjustment

49

second adjustment

50

Bearing surface of the magnet pot

Claims (9)

Solenoid valve-controlled injection nozzle with a nozzle needle, the opening and closing of which is controlled by a magnetic valve, wherein the magnetic valve is located in a magnetic pot (in 20 ) electromagnets ( 18 ), an anchor ( 16 ) and one with a valve seat ( 14 ) cooperating valve member ( 15 ), wherein the armature ( 16 ) with an anchor bolt ( 28 ) connected by a guide sleeve ( 40 ), wherein the magnet pot ( 20 ) the guide sleeve ( 40 ) at least partially, characterized in that the magnet pot ( 20 ) consists of a solid material and a radial slot ( 22 ) and the guide sleeve ( 40 ) and the magnet pot ( 20 ) at least partially by an exemption gap ( 43 ) are separated. injection according to claim 1, characterized in that the Solid material has a saturation induction> 1.9 T has. injection according to claim 1, characterized in that the Solid material has a coercive force <3500 A / m. injection according to claim 1, characterized in that the Solid material is an FeCo alloy. Injection nozzle according to claim 1, characterized in that the armature ( 16 ) a the magnetic pot ( 20 ) facing anchor plate ( 19 ), one end ( 45 ) of the guide sleeve ( 40 ) from the magnet pot ( 20 ) protrudes so that the anchor plate ( 19 ) with energized electromagnet ( 18 ) at the protruding end ( 45 ) of the guide sleeve ( 40 ) and a residual air gap ( 39 ) between the magnet pot ( 20 ) and the anchor plate ( 19 ) is located. Injection nozzle according to claim 5, characterized in that the width of the clearance gap ( 43 ) a multiple of the width of the residual air gap ( 39 ) is. Injection nozzle according to claim 6, characterized in that the width of the clearance gap ( 43 ) at least 8 times the width of the residual air gap ( 39 ) is. Injection nozzle according to claim 6, characterized in that the anchor plate ( 19 ) has a smaller diameter than the magnet pot ( 20 ). Solenoid valve, comprising one in a magnet pot ( 20 ) electromagnets ( 18 ), an anchor ( 16 ) and one with a valve seat ( 14 ) cooperating valve member ( 15 ), the anchor ( 16 ) with an anchor bolt ( 28 ) connected by a guide sleeve ( 40 ), wherein the magnet pot ( 20 ) the guide sleeve ( 40 ) at least partially, characterized in that the magnet pot ( 20 ) consists of a solid material and a radial slot ( 22 ) and the guide sleeve ( 40 ) and the magnet pot ( 20 ) at least partially by an exemption gap ( 43 ) are separated.